Aluminum casthouses often have various restrictions in terms of loading space. After the formation of aluminum ingots, scrap elements (billets) are re-introduced into the heating oven to be melted once again. These billets (ingots having a cylindrical shape) are loaded into a container and then dumped into the oven. Similarly, any additives that are added to the oven, including silica or other materials used to create alloys, are manipulated in a similar manner.
A problem with a majority of dumping apparatuses is that these apparatuses have problems dumping their charges into a partly filled oven without splashing or avoiding contact of the container with the molten aluminum surface in the oven.
For the loading and dumping of billets, the prior art apparatuses use either buckets, or containers with bottom doors. The use of buckets usually implies a dumping of loads from a certain height, thus causing splashes when the billets fall into the molten metal. Containers with bottom doors, on the other hand, have two major inconveniences. First of all, very often the bottom door enters in contact with the molten aluminum metal when it opens. Secondly, the container door opening mechanism is often exposed to extremely high temperatures, which reduces its reliability and life span.
Thus, in order to develop a container that does not enter into contact at all with molten aluminum and which reduces exposition of its components to high heat sources, the conventional container principle has to be rethought.
The prior art apparatuses have another important problem: their containers occasionally fall into the ovens. Consequently, a new grappling principle is required to ensure a better quality of the grip of the apparatus onto the container while maintaining in possible shape and global structure of the containers that were initially developed to optimize the capacity, compactness, loading, dumping, stacking capacity and handling of the containers by truck lifts. A mechanism on the container itself must be avoided in order to reduce any exposition of the mechanism to premature wear. Additionally, the apparatus must hold the container solidly at the end of its arms above the oven and make the container turn completely on its own axis without making the container fall into the oven. This rotation must be done with a perfect control of the movement of the container with an offset distance of approximately 6 feet. Modifications to the design were not supposed to influence the attachment mechanism of the apparatus, which must remain removably attached and compatible with a quick attachment system.
Thus, there is still presently a need for an apparatus which can be used to dump tubs or containers.
With such an apparatus, avoidance of any contact of the containers with molten metal surface is desired. Additionally, the apparatus should reduce risks of plunging the container in molten metal. Moreover, the apparatus should be adapted to allow the dumping of metal without causing splashes, nor submerging the container in molten metal, as the container must not enter into contact with the molten metal in the oven.
The apparatus should allow rotation of the container on its own axis, which allows for furnace loading, even if the furnace is full. The apparatus should also be able to dump billets as far away as possible into the oven, by pivoting the container by at least 180°.
Furthermore, the containers should be designed to facilitate loading with conveyors. Additionally, there is a need for an apparatus that insures quick and safe loading of the container. There is also a need for an apparatus, which increases charging capacity of the containers, which can be heavy duty and be stacked to reduce storage space. Consequently, there is a need to develop a container adapted to the loading and dumping of billets in ovens. Such a container should be able to hold up to 2,000 kg of scrap billets, and dump its load without having the container entering contact with the molten aluminum surface. Charges to be lifted and pivoted are typically around 3,000 kg (billets plus container), on a distance around approximately 6 feet. Hence, the containers are designed to be stacked one on top of the other and can be moved from one place to another with a typical power lift truck. Consequently, the containers must have a balanced structure and must be easy to handle. Additionally, the apparatus must be able to stack the containers in a secure manner.
There is also a need for an apparatus that has as many various uses as possible (e.g. being adapted to different formats and shapes of containers—silica buckets, etc.), and be compatible with a quick attached system. Containers being manipulated by the apparatus must also be able to be manipulated by power lift trucks.
The grasping mechanism of the apparatus must be safe and designed in order to avoid dropping containers into the ovens.
Work being accomplished with this apparatus must be done without having the operator exiting the vehicle holding the apparatus. Grasping of containers on the floor must be done without help or signalmen. Grasping of containers must be executed by the operator of the vehicle only.
The dumping means must be designed to take into account the weight of the containers, the center of gravity of the container being rotated, friction of various components and any offset distance between the vehicle and the containers or boxes that have to be displaced or manipulated.
Thus there is still presently a need for an apparatus which meets the above-mentioned requirements.